Sodium meta bisulfite and ph tolerance ofPleurotus sajor caju under submerged cultivation

To develop a procedure for submerged cultivation of the edible fungusPleurotus sajor caju, we investigated the organism’s tolerance to sodium meta bisulfite and acidic pH levels. These factors were evaluated as means of controlling bacterial and/or fungal contamination. Trials were conducted in 500 mL Erlenmeyer flasks that contained 200–300 mL of a 3% glucose, 0.5% yeast extract medium, and either 0-0.225% SMB (wt/wt) added, or initially adjusted to pH levels between 1.8–6.5. Inoculated flasks were incubated 7–10 d at 30°C and 200 rpm in an environmental shaker, with samples removed daily to determine mycelial dry weights. Results showed that SMB levels up to 0.05% significantly lengthened the lag phase (from 27 to 79 h) but had no effect on productivity. Maximal productivity varied between 0.054–0.057 g/L/h, whereas overall productivity was 0.042–0.045 g/L/h. Biomass concentrations ranged from 7.1–8.4 g/L. Higher SMB levels rapidly reduced productivities and yields, eventually inactivating the inoculum above 0.1% SMB. In one instance the SMB tolerance of P.sajor caju was increased to 0.075% by repeatedly exposing the organism to sublethal levels of the chemical; however, this trait was not maintained in later trials. Bacterial contaminants were detected at SMB concentrations of 0.02–0.07%, while fungal contaminants were found up to 0.125% SMB. Thus it appears that SMB might be useful in controlling bacterial contamination, but may not be as effective against fungal contaminants. The optimum pH range in terms of lag phase length, biomass yield, and productivity was 4.5–5.5, however, in certain trialsP. sajor caju still exhibited good growth parameters at pH levels as low as 3.8–4.0. pH levels below 3.8 and above 5.8 greatly reduced both growth rates and yields. Acidic pH levels (3.8–4.5) were also effective in controlling the majority of bacterial and fungal contaminants encountered. Therefore low pH or perhaps a combination of low pH and SMB should be useful in developing a large scale system for submerged cultivation ofP. sajor caju.     

FTIR reflection spectra and structure of molten chloroaluminates containing alkaline earth chlorides or oxides

FTIR reflection spectra of molten chloroaluminates containing alkali earth chlorides showC _2v andC _3v perturbations of AlCl ₄ ^– . The splitting ofv ₃(F ₂) is proportional to the ionic potential of the counterion. The observation of anion-cation stretching vibrations allows the strength of the interaction to be evaluated. Molten NaAl₂OCl₅ is assumed to contain the Al₄O₂C1 ₁₀ ^2– ion.     

Activation of metallocenes for olefin polymerization as monitored by IR spectroscopy

Binary mixtures of Cp2ZrMe2, Cp2ZrCl2, dimethylaluminum chloride, trimethylaluminum, and methylaluminoxane (MAO), as well as Cp2ZrMe2 with boron-based activators, have been studied by in situ IR spectroscopy (Cp = cyclopentadienyl, Me = methyl). The position of a strong band near 800 cm(-1), corresponding to the out-of-plane vibration of the Cp hydrogen atoms, is sensitive to the bonding environment around Zr and can be used to monitor reactions and the formation of new products in these mixtures. Harmonic frequencies determined by density functional theory correlate well with experimental values and have been used to assist in the interpretation of the data. The frequency of the Cp out-of-plane vibration, ranging from 797 to 832 cm(-1) in our experiments, is found to increase with increasing electron density on the Cp ring and decreasing Zr-Cp distance. In the mixture of MAO and Cp2ZrMe2, a stable complex is rapidly formed at low Al/Zr ratios. A mechanism that may explain the need for a large MAO excess is proposed for the activation of metallocenes with MAO. The proposed mechanism involves the formation of dimers or oligomers of MAO cages that tend to dissipate the charge of the anion. This destabilization of the Cp2ZrMe2-MAO complex facilitates the formation of the catalytically active cation.     

Untersuchung von Fetten und fettartigen Stoffen

Ohne Zusammenfassung     

单节点图的弱最大亏格

单节点图即只有一个点的图.本文讨论了该图类的三种嵌入.并得到了对应的最大亏格.对于这类图的弱嵌入.插值定理是成立的.     

Heat transfer in pool boiling of binary and ternary non-azeotropic mixtures

Heat transfer coefficients in nucleate pool boiling of binary and ternary non-azeotropic hydrocarbon mixtures were obtained experimentally using a vertical electrically heated cylindrical carbon steel surface at atmospheric pressure with several surface roughness. The fluids used were Methanol/1-Pentanol and Methanol/1-Pentanol/1,2-Propandiol at constant 1,2-Propandiol mole fraction of 30%. Heat fluxes were varied in the range 25–235 kW/m². The cylindrical heater surface was polished to an average surface roughness of 0.2 μm, and sandblasted yielding surface roughness of 2.98 and 4.35 μm, respectively. The experimental results were compared to available prediction correlations, indicating that the correlations based on the boiling range are in better qualitative agreement than correlations based on the phase envelope. Increasing surface roughness resulted in an increase in the heat transfer coefficient, and the effect was observed to be dependent on the heat flux and fluid composition.     

A Computational Study of the Homogeneous Algorithm for Large-scale Convex Optimization

Recently the authors have proposed a homogeneous and self-dual algorithm for solving the monotone complementarity problem (MCP) [5]. The algorithm is a single phase interior-point type method; nevertheless, it yields either an approximate optimal solution or detects a possible infeasibility of the problem. In this paper we specialize the algorithm to the solution of general smooth convex optimization problems, which also possess nonlinear inequality constraints and free variables. We discuss an implementation of the algorithm for large-scale sparse convex optimization. Moreover, we present computational results for solving quadratically constrained quadratic programming and geometric programming problems, where some of the problems contain more than 100,000 constraints and variables. The results indicate that the proposed algorithm is also practically efficient.     

On Spanning Disjoint Paths in Line Graphs

Spanning connectivity of graphs has been intensively investigated in the study of interconnection networks (Hsu and Lin, Graph Theory and Interconnection Networks, 2009). For a graph G and an integer s > 0 and for ${u, v \in V(G)}$ with u ≠ v, an (s; u, v)-path-system of G is a subgraph H consisting of s internally disjoint (u,v)-paths. A graph G is spanning s-connected if for any ${u, v \in V(G)}$ with u ≠ v, G has a spanning (s; u, v)-path-system. The spanning connectivity κ*(G) of a graph G is the largest integer s such that G has a spanning (k; u, v)-path-system, for any integer k with 1 ≤ k ≤ s, and for any ${u, v \in V(G)}$ with u ≠ v. An edge counter-part of κ*(G), defined as the supereulerian width of a graph G, has been investigated in Chen et al. (Supereulerian graphs with width s and s-collapsible graphs, 2012). In Catlin and Lai (Graph Theory, Combinatorics, and Applications, vol. 1, pp. 207–222, 1991) proved that if a graph G has 2 edge-disjoint spanning trees, and if L(G) is the line graph of G, then κ*(L(G)) ≥ 2 if and only if κ(L(G)) ≥ 3. In this paper, we extend this result and prove that for any integer k ≥ 2, if G ₀, the core of G, has k edge-disjoint spanning trees, then κ*(L(G)) ≥ k if and only if κ(L(G)) ≥ max{3, k}.